Orders of Genetic Approach:

• After modification, the soils can be grouped into three orders namely, zonal, intra-zonal and azonal based on the zonality concept developed by Russian soil scientist Dokuchaiev.

a. Zonal Soils:

• Soils in this group possess well developed profiles reflecting the influence of climate and vegetation.
• The only differences due to the parent material are rendered subordinate by dominating climate influences.
• Example, laterite soil, podzol soil.

b. Intra-Zonal Soils:

• The soils occur within a zone, but reflect the influence of some local conditions, such as topography and/or the parent material.
• Under these conditions, the characteristics of soils imparted by the local conditions and dominant viz. excess of water, salt, calcium carbonate etc.
• Example, saline sodic and saline sodic soil etc

c. Azonal Soils:

• The soils have poorly developed profiles because of time as a limiting factor.
• The group includes young soils without horizon differentiation so the soils could not be grouped in any one of these two orders (zonal and intra-zonal) and was placed in a separate order known as azonal soils.
• Example alluvial soils.